Oscillograph apparatus



`lme 20, 1939. H. J, SCHRADER 2,162,827

o'scILLoGRPH APPARATUS Filed Dec. 28, 1934 2 sheets-sheet 1 u if H.J. SCHRADER BY gw ATTORNEY,l

Je 20, 1.9397. H. J. scHRADER OSCILLOGRAPH APPARATUS 2' Sheets-Sheel'l 2 Filed Dec. 28Iv 1934 lNvEN'roR ATTORNEY atented june i539 n APPARATUS acme J. schmaler, ncdconncigms, N. J., cssignor to o Corporation of America, a corporation of Delaware Application December 28, 1934, Serial No. 760,062

s ci.- (ci. ris- 183) The present invention relates to oscillomaph apparatus and particularly to devicesior. use in connection therewith so as to control the operation and the form of the wave trace appearing upon the device.

In accordance with the present invention the cscillograph apparatus has been illusie-ated as comprising a cathode ray tube and itis an object of the invention to provide a means for controlling particularly the usual sweep circuit oscillator so that the deflection of the resulting cathode ray beam bears a pre-established relationship to the phenomena to be observed on the uorescent viewing screen of the tube.

More particularly, the device to be herein dislclosed is for controlling the periodicity of an oscillator circuit used to control the sweep frequency of a cathode ray beam in 4oscillographic apparatus. This control may be accomplished, for example, by controlling the periodicity of discharge of a grid-controlled discharge tube of the type used in many sweep circuit control systems, for example, that disclosed by A. W. Vance in his co-pending application Serial No. 544,959.

The invention in its present form nds particular application to use in connection with the alignment of radio circuits so that whatever adjustments may be made may be checked with great ease by observing the pattern of the wave trace appearing upon the fluorescent viewing screen of the tube.

Other objects of the invention are to provide apparatus oi the nature abovesuggested and of the type to be hereinafter described which may operate in conjunction with known and existing types of oscillograph apparatus and also to provide an impulse generator which will be relatively simple in its construction and arrangement of parts, which can be manufactured cheaply and which will be extremely efficient in its operation.

Still other and further objects and advantages of the invention will become apparent by referring to the accompanying drawings in connection with the following speciiication. vBy the accompanying drawings the device has been illstrated in one of its preferred applications and as shown,

Fig. l represents schematically a circuit diagram of a complete operating system; and

Fig. 2 represents schematically the generell form'cf wave trace whichI will appear upon the uorescent viewing screen of the tube when the device is operated in the particular application to which it has been applied herein for the purpose of disclosing one of themany possibll eral arrangements thereof. If reference is now madezto the accompa drawings, it will be seen that there is pri a cathode ray tube l which includes the electrode elements comprising-the cathode ber 3 heated by the usual type of heater ell 5. Immediately surrounding the cathode grid or control electrode l to vary the inten: the cathode ray beam when varying vo are applied to the grid. The anode mem completes the formation of the electron gun which a cathode ray beam H is projecte ward the fluorescentv material coating the surface ci the end i3 of the tube. In orc provide a suitable electrostaticiield for the pose of focusing the electron beam passin yond the anode 9 and also to accelerate the duced electron stream in its passage towar iiuorescent viewing screen, there is provi( second anode l5 to which a voltage conside higher than that applied to the first anod impressed'.

As shown by the drawings, the electron l l is suitably deflected from both a horizont: a vertical plane by means of suitable electro deecting elements ll, l1 and I9, i9, alti it is to be understood that electromagneti necting systems, or a combination of electro ,and electromagnetic deflectlng systems, cou

substituted Without changing in any wa: manner in which the device is to be operate( was disclosed in the above-mentioned applic of A. W. Vance, saw-tooth electrical wave supplied to the deiiecting electrodes so as to the beam to be noved at an appropriate across the iiuorescent viewing screen. Vbeam controlling electrical impulses, which be assumed to be produced through the discl of an electrical charge stored in a condense ment and the discharge current suitably a iied, as has been disclosed by the aforesaid l application, is indicated herein as having produced in the conventional type ofsystem erally designated 2l.

According tc the disclosure of A. W. Vanc controlling impulses applied for deiiection poses may be suitably produced so as to ac pany received television signals andafter su separation may be usedto control the operatil the beam deiiecting system. By the preser vention, these impulses are locally geeraten appliedjto the horizontal beam deflection c( system by way of an impulse generator co1 tionally i designated 23. The impulse gene relatively simple form of wound stator iose output energy is'y supplied to the The impulse generator per se con- Itively small permanent magnet 25 or, ed, an electromagnet on whose two re ,coils which are connected in series ',her and with the deflection control rn in which the invention has been two pole iron rotor element 21 is revolve between the pole pieces ofthe lo as to change the magnetic flux coils and thus produce a suitable `oltage in the deflection control sysis rotor element is preferably con- ;he shaft 29 of a suitable drive motor m any desired power line connection. lily be seen that by suitably shaping as and varyingthe shape of the rotor r by varying the 'spacing between the nd the rotor element, that the wave the developed voltage may be varied. shaping and spacing the rotor and its, it is possible to generate a sooth wave or to generate a wave which t very high degree. ion with uses of the device for the if synchronizing the beam deflection n 2|, las would be the case when the )f the general character disclosed by iplication, the stator and rotor elelmpulse generator are so designed as peaked wave formation in which the ise from a minimum 4to a maximum ntaneously and then immediately minimum value. However, if the Iator 23 is to be'used forV the purpose the saw-tooth wave formation for ses, the conductors 33 and 35 shown r with the deflection control system connected with the deiiecting ele- Jregoing. it can readily be seen that Ly beam I i developed within the tube so as to sweep rapidly in a horizoni right to left, for example, and `then ost instantly to its startingA position nensurate with the rate at which the thus the rotor element 31, turns so of traversal for each cycle of the 1 and forth across the tube 4may be ying the speed of the motor in any er. Liar application of the device herein r use in connection with a cathode ph system for radio receiver aligns particular use of the device, there n the same shaft with the impulse r and the motor, the rotor plates 31 r system generally designated at 39 es also fixed stator plates 4l. The onsof the rotor elements 21 of the ator 23 and the condenser plates 31 s use should preferably be such that E the poles of the rotor is such as to aximum voltage output when the ites are totally unengaged. The nents 39 comprising the rotor plates tor plates 4I are then connected in ;he main tuning capacitor 43 of the iit conventionally shown as 45. ar which has been illustrated for the closing one form which this invenne is the conventional type of osciln the art as the Hartley oscillator which comprises an inductance element- 41 connected between plate and grid electrodes of a tube 49 between whose terminals the main tubing .capacitor 43 is connected. .The output of the `oscillator system Vis supplied through the winding 49 to the circuit under testl which may be assumed to include thecircuit comprising thej winding 49 and thetube 53 and in'which even 'the input circuit of the tube 53 is tuned t thefnorrnal fre--` quency of the oscillator system 45.' The voltage appearing in the circuitA under test is then supplied to a rectifier system herein shown' conven- -tionally as 55 which comprises, for example', a diode 51 and after yrectification the output 'from the detector, if necessary, is vsuitably amplified in the amplifying tube system59. This outl put' voltage is applied to the vertical 'denecting "systeml9, I9 of the cathode ray tube I. Thus, it can be seen.that -the deflection of the' electron beam in a vertical direction of the tube I`is at every instant directly proportional to the voltage in the circuit 49, 5l,'53 which is under test.

If, now, itis assumed that the variation in position of the rotor plates 31 with 4respect y'tn the stator plates .4I in thecondenser 39 is suohato vary the normal frequency ofthe oscillator system by an amount of the order of 2 percent, it can be seen that the vertical wave trace produced uponthe cathode ray tube will-be in accordance with the showing 4in Fig. 2.. When so operated the first left to right trace of the cathode ray across the fluorescent screen coating the innerA end wall i 3 of the tube will be represented so that the trace will first represent a frequency less than that to which the tube circuit is tuned and then the frequency value representedwill progressively increase to a value greater than that which the. circuit 49, 5| is tuned, -while for the next successive wave trace the frequency represented will first be greater than that -to 'which the circuit 49, 5I istuned and then progressively changed to a value less than that toiwhichthe same circuit is tuned. All subsequent'lrepresentations will a1- ternately be repetitionsy of, the two above exe plained and the transient effect observable upon the'screen will be a resonance curve of the cir cuit under test. .Y A

The invention has, of course, been illustrated in only o'ne of the several form whichit may assume, but many and varied-modifications may readily be made without departing from the spirit and scope of the foregoing disclosure and,'there fore, it is assumed that any and all modifications may be utilized'which fall fairly within the spirit and scope of the hereinafter appended claims. Having thus described the invention; what is claimed and desired to secure by'Letters Patent is the following:

1. In oscillograph apparatus, a cathode ray tube having means therein to produce an electron .60 beam and a system of defiecting-electrodes for causing the beam produced to trace' predetermined paths across the viewing screen of the tube upon the application of electrical energy thereto', an impulsegenerator adapted to generate` electrical wave forms of predetermined characteristic means for developing electrical energy of predetermined wave formationm'ieans to control the frequency oi the developed electrical energy in accordance with the impulse frequency of the impulsegenerator means to supply to the de'liecting system'A the developed electrical energy to control the motion of the electron beam i'n at least one of a-plurality of transverse deflection paths and means to control the beam by electrical energy whose frequency varies cyclically between two predetermined values.

2. An electronic device comprising a circuit Ito be tested, a thermionic oscillator coupled with said circuit for supplying energy thereto, means to vary progressively the output energy frequency of the oscillator between maximum and minimum and minimum and maximum values, an impulse generator for developing electrical impulses of frequency corresponding to twice the rate of change of the oscillator frequency between successive maximum or minimum values, an electronic oscillograph, a deilection controlk device for controlling the deflection of the oscillograph beam in one plane, means for controlling the deection frequency produced by the control device in accordance with the energy output of the impulse generator, and means to control the deection of the oscillograph beam in a perpendicular plane in accordance with the frequency of the energy developed in the thermionic oscillator and transferred through the circuit to be tested.

3. The method of testing circuits which comprises supplying electrical energy to the circuit, cyclically varying the frequency of the supplied -energy between two predetermined values ata pre-established rate, controlling an electronic beam motion from the output energy of the ener-` gized circuit to be tested, developing electrical energy of a frequency related in a predetermined manner to the frequency of the supplied cyclically varying energy, controlling the electronic beam in a perpendicular direction to the first control, synchronizing the last mentioned beam control by the developed electrical energy of frequency related to the cyclically varying frequency energy, and tracing in accordance with the two separate beam controls a visible record of the characteristic of the circuit tested.

4. The system claimed in claim 1, wherein the second named means to control the beam comprises an oscillator of substantially constant frequency, a variable condenser system, means for continually changing the position of the condenser rotor with respect to the stator at a rate corresponding to the frequency of repetition of said impulses developed by said generator, a circuit of which the electrical characteristic is to be measured, said circuit having its output connected with the electron beam de flecting means for controlling the beam deflection in a plane transverse of the direction of control exercised by the generator, and means to change the/oscillator frequency by variation of the condenser, and means to supply the energy of the oscillator to the circuit.

5. The method of controlling the deflection of a cathode ray beam as a function of the instantaneous value of a capacity of a tuned circuit, which comprises developing a source of deilection voltage, developing a source of synchronizing signals, controlling the source of deflection voltage by the developed synchronizing signals and controlling both the value of the capacity and the frequency of the synchronizing signals by common energy.

6. In combination, a variable electrical oscillator, a circuit to be tested, means to supply energy from the oscillator to the circuit to be tested, a

cathode ray tube having a mutually perpendicular deecting system, means to supply energy from the circuit to the deecting system, an unstable saw-tooth generator,' means to supply control impulses to the generator, and common means for varying the frequency of the oscillator and the control impulses.

7. In combination, a variable capacity thermionic oscillator, a cathode ray tube including electrostatic beam deflecting means, a source oi periodic voltage, a saw-tooth generator, an electric circuit, mechanical means interconnecting the variable capacity and the source of periodic voltage, and electrical means interconnecting the oscillator, the electric circuit, the saw-tooth generator, and the cathode ray tube.

8. In an electrical response analyzing system, the combination of a tunable thermionic oscillator, a variable capacity electrically connected to said oscillator, a cathode ray tube including beam deflecting means, an electric circuit to be tested, means to excite the circuit by the oscillator means connecting the circuit to the beam deflecting means, an unstable saw-tooth generator, common means to control simultaneously Ithe variable capacity and the unstable oscillator, and means connecting the saw-tooth generator to the beam defiecting means whereby a trace of electrical response of the said circuit is produced.

HAROLD J. SCHRADER. 

